The cited literature "Technik des Flexodrucks" ("Technology of Flexo Printing", Coating Textbooks) page 2.5, describes an inker with a minimum number of rollers used to ink a plate cylinder or a forme cylinder, by using an ink application roller which has a screen-type surface. Surfaces of this type, as known, are usually either made of metal or ceramic. Ink transfer rollers of this type are usually engaged by a doctor blade. It is practically impossible to individually control the quantity of ink being transferred by engagement of a doctor blade with a profiled surface which is metallic or ceramic. It is also known to control the ink quantity being applied by utilizing rollers of different types of profiled surfaces, that is, of different screen-mesh for example. This permits application of defined quantities of ink. Page 3.13 of the aforementioned textbook describes and recommends such an arrangement.
Stocking ink transfer rollers having different surfaces for different applications causes storage problems and, further, results in excessive installation and re-installation costs, if rollers are to be changed merely because the ink supply needs to be changed. It is also not possible to engage an ink application roller with a hard surface, such as a metallic or ceramic surface directly on a forme cylinder which, likewise, has a hard surface.